The seven dwarves, seven days of the week, the seven seas... These are just a few pop cultural examples that may help explain why 7 is the world's favorite number, at least according to British mathematics writer Alex Bellos. (Bellos recently conducted a survey asking people around the world to share their favorite number; he received 44,000 responses. 7 won, 3 came in second, followed by 8, then 4. Now you know!)

Had he asked us, we probably would have said 7, too. Why? I think you know where I'm heading with this...